Chocolate Ganache Cakes with White-Coffee Foam

PreparationMake coffee foam: Toast coffee beans with brown sugar in a 2-quart heavy saucepan over moderately low heat, stirring constantly to evenly toast beans, until sugar is melted and beans are color of almond skins, 12 to 15 minutes. Add coconut milk and simmer (mixture will bubble up and steam, and sugar will harden), stirring occasionally, until sugar is dissolved, about 5 minutes. Pour through a sieve into a metal bowl and stir in cream. Set metal bowl in a larger bowl of ice and cold water to chill, stirring occasionally. Transfer sauce to siphon and screw on top tightly. Unscrew charge holder from head and put in a charger. Reattach charge holder and screw on tightly. Gas will be released into siphon (with a whooshing sound) within a few seconds. Chill filled siphon at least 1 hour to produce a stiffer foam. Remove and discard first charger. (As you unscrew charge holder, you’ll hear a brief hissing sound.) If fitting from holder comes out attached to charger, just remove charger and reattach fitting. Screw on second charger and chill at least 15 minutes (longer if a test of foam is not thick enough). Make cakes: Preheat oven to 400°F. Butter and flour 8 (4-oz) ramekins, knocking out excess flour, and put on a baking sheet. Whisk together whole eggs, yolks, and sugar until combined well. Melt chocolate and butter in a double boiler or a metal bowl set over a saucepan of simmering water, stirring. Remove top of double boiler or bowl from heat and whisk egg mixture into it. Sift flour evenly over chocolate mixture and fold in until just combined. Divide among ramekins and bake in middle of oven until cakes begin to puff but centers are not set, 12 to 13 minutes. Shake siphon well, about 1 minute. Turn upside down and press lever to fill a bowl with coffee foam. Serve cakes in ramekins with coffee foam on the side.

PreparationMake coffee foam: Toast coffee beans with brown sugar in a 2-quart heavy saucepan over moderately low heat, stirring constantly to evenly toast beans, until sugar is melted and beans are color of almond skins, 12 to 15 minutes. Add coconut milk and simmer (mixture will bubble up and steam, and sugar will harden), stirring occasionally, until sugar is dissolved, about 5 minutes. Pour through a sieve into a metal bowl and stir in cream. Set metal bowl in a larger bowl of ice and cold water to chill, stirring occasionally. Transfer sauce to siphon and screw on top tightly. Unscrew charge holder from head and put in a charger. Reattach charge holder and screw on tightly. Gas will be released into siphon (with a whooshing sound) within a few seconds. Chill filled siphon at least 1 hour to produce a stiffer foam. Remove and discard first charger. (As you unscrew charge holder, you’ll hear a brief hissing sound.) If fitting from holder comes out attached to charger, just remove charger and reattach fitting. Screw on second charger and chill at least 15 minutes (longer if a test of foam is not thick enough). Make cakes: Preheat oven to 400°F. Butter and flour 8 (4-oz) ramekins, knocking out excess flour, and put on a baking sheet. Whisk together whole eggs, yolks, and sugar until combined well. Melt chocolate and butter in a double boiler or a metal bowl set over a saucepan of simmering water, stirring. Remove top of double boiler or bowl from heat and whisk egg mixture into it. Sift flour evenly over chocolate mixture and fold in until just combined. Divide among ramekins and bake in middle of oven until cakes begin to puff but centers are not set, 12 to 13 minutes. Shake siphon well, about 1 minute. Turn upside down and press lever to fill a bowl with coffee foam. Serve cakes in ramekins with coffee foam on the side.